31–40 of 86 posts
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How much does this stuff cost?
I don't think they do regular consumer stuff, it looks like everything is special order. According to this page [1], you have to contact one of their business partners in order to arrange any purchases. [1] http://www.maxwell.com/products/microelectronics/where_to_bu...
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I doubt the warhead has code to control its activation--more likely it's something like an altitude sensor that controls detonation.
Think cruise missile. Some code looks at a map, looks at GPS, looks at altitude and velocity, and decides "Yup, this is the spot." It's probably a lot more prosaic than I imagine.
I've wondered about the following: The firmware controlling a nuke has to have, at some point, a bit or control register it sets that causes the explosion to go off: *pKaboom = true; or something like that. My question is: What is the line of code after that? *pKaboom = true; /*NOTREACHED*/ I suspect it's more complicated than that (there's an infinite loop of some kind that keeps retrying the command sequence). I al…
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exit(EXIT_SUCCESS); // or maybe failure, if we reach this point? :)Earlier quoted context omitted.
Doesn't the difficulty/expense of keeping all those processors running in absolute cycle-for-cycle lockstep increase dramatically with the amount of redundancy? I vaguely remember being taught that this is the big problem developing real-time safety critical systems.
If you make a bunch of (highly redundant) small processors, then I don't see why it would be much harder than the clock distribution issues in large processors, which also need to keep all their parts in sync. Alternately, it's possible to use asynchronous processor design and not worry about clock distribution. The tools aren't really there, but there have been async processors made before, and they work. They handl…
I've wondered about the following: The firmware controlling a nuke has to have, at some point, a bit or control register it sets that causes the explosion to go off: *pKaboom = true; or something like that. My question is: What is the line of code after that? *pKaboom = true; /*NOTREACHED*/ I suspect it's more complicated than that (there's an infinite loop of some kind that keeps retrying the command sequence). I al…
Earlier quoted context omitted.
Think cruise missile. Some code looks at a map, looks at GPS, looks at altitude and velocity, and decides "Yup, this is the spot." It's probably a lot more prosaic than I imagine.
I'm fairly certain that ICBM's use inertial guidance with predefined/computed coordinates ( http://en.wikipedia.org/wiki/Inertial_guidance ). There's no software involved, its all physical. Detonation is (probably) trigged by a combination of altimeter, accelerometer and other telemetry systems.
Earlier quoted context omitted.
I don't think they do regular consumer stuff, it looks like everything is special order. According to this page [1], you have to contact one of their business partners in order to arrange any purchases. [1] http://www.maxwell.com/products/microelectronics/where_to_bu...
Presumably someone in the US government will then hear about the interesting fellow trying to buy nuclear-hardened equipment.
(But I don't think I need the cavity search every time I enter the US that might come along with that...)
Now try to imagine something using this part in such a way.
/* NED low. Turn off life support. Insurance companies now vapor."
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No kidding. I believe NASA had something like 3 dual-redundant flight computers on the Voyager probes.
Just think how much redundancy you could get, cheaply, with the advances that have been made with Moore's Law over the years. Computers for space probes don't need to be that fancy. It's totally feasible to build processors that use error-correcting codes in their entire datapaths, have tri-modular redundancy for all their functional units, and then are arranged alongside several other identical processors for ridicu…